The invention relates to a method and system for diagnosing and repairing operational faults on a machine, and more specifically to accessing remotely located information to assist with the diagnosis and repair.
The diagnosis, maintenance and repair of a complex system used in industrial processes, medical imaging, telecommunications, aerospace applications, transportation, and power generation involves extremely complex and time consuming processes. Efficient and cost-effective operation of the machine requires fast and accurate diagnosis of machine faults, followed by a repair to return the machine to operational status.
The conventional diagnosis and repair process for most machines is based on the experience of the field engineer, in conjunction with the use of paper-based service information describing the components and operation of the machine. In some situations, a performance log may be available as an aid to the diagnostic process. Such performance logs can be created manually by the machine users or generated automatically by the machine itself. After examining the symptoms displayed by the machine and entries in the performance log, the field engineer uses his accumulated experience and training to map incidents occurring within the machine to one or more potential faults that may be causing these incidents. For simple problems with simple machines, this process works well. However, if the problem is complex and the root cause difficult to discern, the experienced field engineer may be unable to identify the problem. In that case, the machine is rendered out of service and the machine or at least a suspect part of the machine is returned to a repair center for further analysis and repair or replacement. The inability of the field engineer to accomplish the repair on-site creates a cost for the machine owner while the faulty machine is out of service during the pendency of the repair.
Some complex machines incorporate diagnostic processes and sensors that can automatically report faults and machine operational parameters. Typically, to diagnose a fault in such a machine, a field engineer studies the fault log and the operational parameters as an aid to determining the root cause of the fault. Although the fault log can provide helpful diagnosis information, the field engineer also relies substantially on her prior experiences with the machine (or similar machines) to make a full and complete diagnosis and successful repair.
To perform the diagnosis and repair, the field engineer uses service documentation, including block diagrams, exploded diagrams, parts lists, assembly drawings, schematics, etc. The documentation may be applicable only to a specific machine model number; it usually will not be unique to the specific machine undergoing diagnosis and repair. Obviously, as the complexity of the machine increases, the amount of paper needed to describe the machine and assist with the diagnosis and repair process likewise increases. Again, the field engineer relies on his experiences with the machine, and others like it, in conjunction with the paper-based information, to perform the diagnosis and subsequent repair.
Yet another problem with a paper-based system as applied to complex machines, is the variety of machine configurations, with each having its own unique service documentation. During the production run of a given model, there may be multiple redesigns and changes. Thus, the paper-based service documentation, which is usually based on a specific model number, may not accurately reflect the technical content of a specific machine bearing that model number. When the problems associated with model run changes are considered in light of a paper-based system, there is presented an inordinately complex and unmanageable problem of locating the correct service documentation for a specific machine.
In addition to the standard service documentation, it would also be desirable for the field engineer to have access to design information created during the design of the machine by the design engineering personnel. Such detailed information may help the field engineer understand the interrelationship of various machine components. Failure mode and effects analysis and fault tree documentation can also advantageously aid the field engineer in correctly diagnosing the machine fault. Unfortunately, frequently the repair activity is undertaken without detailed knowledge of the system design and the system design is undertaken with little input from field engineers having responsibility to repair the machine.
One problem that has been noted with field service repairs is the tendency of the field engineer to fix problems with which they are familiar, rather than undertaking a complete and thorough analysis to identify the root cause of the problem and fix it. For example, a field engineer may be familiar with an air conditioner problem typically caused by a faulty switch. Unknown to the field engineer, engineering personnel may have redesigned the switch so that it is now much less likely to be the culprit when a given fault occurs. However, the field engineer, being unaware of the redesign, will continue to replace the switch whenever he encounters a fault which had previously been resolved by replacing the switch. The result will be a failed repair.
Briefly, in accordance with one embodiment of the present invention, a method for analyzing a fault condition on a machine comprises: receiving fault symptoms to provide a fault analysis; automatically attempting to determine a probable cause of the fault; if a probable fault cause is determined, automatically generating an indication of the fault cause; and, if a probable fault cause is not determined, automatically generating a return code associated with the fault symptoms and the fault analysis.
In accordance with another embodiment of the invention, a method for use by a field engineer for analyzing a fault condition on a machine located at a machine site comprises: at the machine site, providing information to an analysis tool for analyzing the fault, wherein the information is provided by the field engineer as queried by the analysis tool, and wherein a plurality of individual queries and field engineer responses constitute a search path; if the analysis tool determines the probable cause of the fault, repairing the machine at the machine site based thereon; and, if the analysis tool is unable to determine the probable cause of the fault, assigning a return code prior to moving at least a part of the machine to a repair center, wherein the search path is associated with the return code.